Transmittance of finite-energy frozen beams in oceanic turbulence

Received Probability of Orbital-Angular-Momentum Modes Carried by Diffraction- and Attenuation- Resistant Beams in Weak Turbulent Oceans

“…Therefore, we must use stochastic statistical theory to determine the superposition coefficients. Utilizing the zero mean Gaussian random field statistical method, we can determine the light intensity of the DARR beam on a cylindrical surface of radius r = r 0 for 0 ≤ z ≤ L in the following relation [17] |E…”

“…As the beam propagates through the oceanic turbulence, the eigenstate of OAM carried by the DARR beam is no longer guaranteed to be in the original eigenstate of OAM. However, by the superposition theory of waves, the disturbed field of the DARR beam can be decomposed into a series of spiral harmonics e il ϕ with expansion coefficient B l as follows [10,17]…”

“…With the increasing demand for underwater resource development and utilization, the study of underwater optical communication systems with high information capacity has become a research hotspot in the field of underwater optical communication networks [1][2][3][4][5][6]. Recently, it has become one of the main targets of researchers in this field to improve the theoretical channel capacity of the optical communication system or to control the channel attenuation and channel capacity by selecting a new signal source (beam) [7][8][9][10][11][12][13][14][15][16][17], using adaptive optical systems [18] and by utilizing optimized signal coding technology [19][20][21]. It is well known that the orbital angular momentum (OAM) mode, carried by photons, provides a new dimension that can be encoded [22], and that the OAM module is related to the spatial distribution of wave function [22].…”

“…Therefore the OAM eigenstates (modes) offer the possibilities of realizing arbitrary base-N quantum states and higher capacity optical communication [23], and there is considerable interest in underwater optical communication. However, the spatial nature of the OAM carrier suggests that it may be susceptible to the disturbance of oceanic turbulence [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] as well as the absorption of seawater [1,17]. Choosing a special optical signal carrier is one of the effective methods to weaken the turbulent diffraction disturbance or absorption of seawater, so many research results have been reported on the propagation of scalar non-diffraction vortex beams in turbulent seawater, and great progress has been made based on different methods [7][8][9][10][11][12][13][14][15][16][17].…”

“…Further, it was found that Gaussian pulsed X waves and Bessel-Gaussian localized vortex waves [15,16], through turbulent seawater, is higher than that of Laguerre-Gaussian beam in terms of resisting the effects of turbulence. To understand the characteristics of frozen wave resistance diffraction and absorption, Deng et al [17] established a transmittance model for finite energy frozen beams and analyzed the diffracting-and absorption-resistance of finite energy frozen waves from the beam transmission wavelength, beam waist, beam OAM quantum number, inner scale and outer scale of turbulence, and the ratio of temperature to salinity. By designing longitudinal profile, one can partially compensate the attenuation loss of the transmittance.…”